Thailand’s Army commander urged Prime Minister Somchai Wongsawa Wednesday to step down and call elections as he appealed to protesters who have paralyzed the country’s main international airport for two days to cease their demonstrations and leave the terminal.

“The government should return power to the people,” the commander, Gen. Anupong Paochinda Anupong, told reporters after meeting with business leaders.

In a country with a history of military coups, including one just two years ago, General Anupong’s statements carried particular weight. “We will not seize power from the government,” he said. “We are just making a suggestion and will let the government decide.” But a government spokesman rejected the commander’s appeal and said the prime minister would not call new elections, Reuters reported.

The blunt recommendation from the army came as protesters consolidated their control over Suvarnabhumi Airport, forcing the cancellation of all flights Wednesday in an audacious challenge to the government and a major blow to the Thai economy.

Protesters seized the control tower at midday Wednesday after spending the night in the terminal.

“I am often asked whether we will stop our protests if the prime minister resigns,” Sondhi Limthongkul, one of the leaders of the protests, told a crowd of cheering supporters in front of the airport’s departure hall. “You must quit first and then we will sit and talk.”

Confidently striding across a makeshift stage, Mr. Sondhi added: “Are we going to stay here tonight? The answer is definitely, Yes!” Stranded passengers were evacuated by airport staff from the terminal throughout the day Wednesday, many of them sent to Bangkok hotels. “Canceled” flashed across the flight schedule screens and check-in counters were empty.

Protesters set up cooking equipment and prepared vats of food in the terminal building, giving parts of the building a festival-like atmosphere. But with tension running high among both demonstrators and government supporters, the possibility of further violence remained high.

Assailants threw four explosive devices at anti-government protesters in pre-dawn attacks Wednesday, including one that targeted a group near the airport. At least three people were injured, police told The Associated Press.

The United States Embassy in Bangkok advised Americans to “stay away from the airport given the potential for violence and civil disobedience.”

By shutting down the airport, protesters are ultimately holding the country hostage, analysts say.

“The gateway to the country is now blocked,” said Panitan Wattanayagorn, a professor of political science at Chulalongkorn University in Bangkok. “This is an acute problem for the government.”

Suvarnabhumi is the world’s 18th largest airport in terms of passenger traffic. It is the main conduit for tourists and businesspeople arriving in Thailand and is a major transit hub for Southeast Asia.

Outside the departure terminal, anti-government protesters blocked the main access road, while others roamed the terminal handing out fruit and other food to exasperated travelers.

Officials closed the airport around 9 p.m. Tuesday “for the safety of all passengers.” “I’m very worried about the situation now,” said Sereerat Prasutanon, director of the airport. “I think it’s time that the army comes out and helps to take care of the situation.”

“I was aware there was a political situation in Thailand, but I wasn’t expecting this to happen,” said Keith Torluemke, an American software company employee from San Francisco who had been on vacation in Thailand. “I was going to get home on Thanksgiving afternoon.”

The airport was seized Tuesday by men wielding metal rods who pushed past riot police, marking a sharp intensification of three years of intermittent protests that have tarnished Thailand’s long-standing image as a freewheeling but stable nation.

A series of extreme measures by protesters, including a violent clash with government supporters on Tuesday in Bangkok that left 11 people injured, has brought the government near collapse and left Thailand’s democracy teetering.

The government has struggled to carry on its business while trying to quell the most recent demonstrations, but has found itself consumed by the stalemate. A sit-in at government offices forced Mr. Somchai to conduct business elsewhere.

This week, protesters began what they called a final push against the country’s leaders. They prevented one important parliamentary session, and have said they plan to prevent any future sessions or Cabinet meetings, effectively paralyzing the government.

The protesters, a loose coalition of royalists, academics and members of the urban elite, say they are frustrated with years of vote-buying and corruption. Many are also skeptical of Thai democracy in its current form and propose a voting system that would lessen the representation of lower-income Thais, whom they say are particularly susceptible to vote-buying.

The latest protests come amid anxiety over the health of the ailing 80-year-old King Bhumibol Adulyadej and worries about royal succession. There is also frustration about an underperforming national economy that has not been able to move beyond low-cost manufacturing.

The recent protests, like most of those over the past three years, have centered on Thaksin Shinawatra, the former prime minister, who was removed from power two years ago in a military coup. Protesters accuse the current government, and the one before it, of being Mr. Thaksin’s proxies.

Mr. Thaksin was recently convicted in absentia of abuse of power and remains in exile. The current prime minister is Mr. Thaksin’s former brother-in-law.

During the face-off with riot police officers on Tuesday, one protester said she was willing to die if necessary. “If they shoot, let them shoot,” said Pranee Rattanatakerngporn, a 55-year-old protester who traveled to Bangkok from the northern city of Chiang Mai. “I will stay here until we win.”

Among the passengers stranded at the airport was Anna Plahn, a 34-year-old from Sweden wrapping up a vacation with her two young children. “My two kids are sick and they want to go home,” she said.

“This is the worst thing that has ever happened to us.”

On Tuesday, thousands of protesters were camped out on the main entrance ramp to the airport, blocking traffic to the departure terminal. They spread razor wire on the road to limit traffic, which was allowed to trickle through. A truck parked in front of the terminal served as a makeshift stage where a well-known actor, Saranyu Wongkrachang, led the crowd of protesters in song throughout the night.

The protesters, who had mainly confined their demonstrations to their sit-in at the government compound, took to the streets Monday, when they forced the cancellation of Parliament and temporarily cut electricity supply to the police headquarters.

On Tuesday, thousands of protesters kept the government on the run, blocking the entrance to its temporary offices north of the city and massing in front of army headquarters.

In the late afternoon a clash erupted between protesters and government supporters. Television showed two protesters shooting handguns in the direction of the government supporters and beating them with metal rods and sticks. There were no reports of deaths on Tuesday.

The video also showed protesters surrounding a motorcycle taxi driver and holding a knife to his throat as he clasped his hands together, begging for mercy. Mr. Thaksin has many supporters among taxi drivers. It was unclear what happened to the man.

With nearly daily protests taking place in Bangkok for the past six months, many Thais have grown frustrated.

The print news media, which has been generally critical of the government and supportive of the protests, has recently run articles skeptical of the daily street demonstrations.

One columnist in the Nation newspaper on Tuesday called the protests a “never-ending saga that is futile and a drain on society.”

But the People’s Alliance for Democracy, the group leading the movement to unseat the government, still has a loyal following. The latest spate of protests began in April, but became more serious in August, when the alliance took over the prime minister’s office compound, forcing the previous prime minister to operate out of the VIP terminal of Don Muang Airport, the capital’s older airfield, which is now used exclusively for domestic flights.

On Monday, protesters blocked access to the offices at Don Muang.

“You don’t have to doubt what we will do next,” Somsak Kosaisuk, a protest leader, said Tuesday from a temporary stage set up at Don Muang airport. “First, we will not let the cabinet use this place for their meetings anymore. Second, wherever they go for their meetings, we have our special troops that will follow them.”

A cabinet meeting had been planned for Wednesday, but government officials said it might be pushed back.

The prime minister was scheduled to return late Wednesday from a trip to Peru, where he attended a summit meeting of Asian and Pacific leaders.

As the Thai economy slows down as the global financial crisis causes ripples here, and as the stalemate between the government and the protesters deepens, many Thais are hoping for a resolution.

“How is it going to end?” said Bharavee Boonsongsap, a 34-year-old producer for MTV Thailand. “I keep asking people but they have no answer.”

“Thais are fighting Thais,” she said. “People have become aggressive, and even children have been taught to hate the opposite side.”

New York Times